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<div class="titlepage"><div><div><h3 class="title">
<a name="the_boost_algorithm_library.Misc.is_palindrome"></a><a class="link" href="is_palindrome.html" title="is_palindrome">is_palindrome</a>
</h3></div></div></div>
<p>
        The header file 'is_palindrome.hpp' contains six variants of a single algorithm,
        is_palindrome. The algorithm tests the sequence and returns true if the sequence
        is a palindrome; i.e, it is identical when traversed either backwards or
        frontwards.
      </p>
<p>
        The routine <code class="computeroutput"><span class="identifier">is_palindrome</span></code>
        takes a sequence and, optionally, a predicate. It will return true if the
        predicate returns true for tested elements by algorithm in the sequence.
      </p>
<p>
        The routine come in 6 forms; the first one takes two iterators to define
        the range. The second form takes two iterators to define the range and a
        predicate. The third form takes a single range parameter, and uses Boost.Range
        to traverse it. The fourth form takes a single range parameter ( uses Boost.Range
        to traverse it) and a predicate. The fifth form takes a single C-string and
        a predicate. The sixth form takes a single C-string.
      </p>
<h5>
<a name="the_boost_algorithm_library.Misc.is_palindrome.h0"></a>
        <span class="phrase"><a name="the_boost_algorithm_library.Misc.is_palindrome.interface"></a></span><a class="link" href="is_palindrome.html#the_boost_algorithm_library.Misc.is_palindrome.interface">interface</a>
      </h5>
<p>
        The function <code class="computeroutput"><span class="identifier">is_palindrome</span></code>
        returns true if the predicate returns true any tested by algorithm items
        in the sequence. There are six versions: 1) takes two iterators. 2) takes
        two iterators and a predicate. 3) takes a range. 4) takes a range and a predicate.
        5) takes a C-string and a predicate. 6) takes a C-string.
      </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">BidirectionalIterator</span><span class="special">&gt;</span>
	<span class="keyword">bool</span> <span class="identifier">is_palindrome</span> <span class="special">(</span> <span class="identifier">BidirectionalIterator</span> <span class="identifier">begin</span><span class="special">,</span> <span class="identifier">BidirectionalIterator</span> <span class="identifier">end</span> <span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">BidirectionalIterator</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Predicate</span><span class="special">&gt;</span>
	<span class="keyword">bool</span> <span class="identifier">is_palindrome</span> <span class="special">(</span> <span class="identifier">BidirectionalIterator</span> <span class="identifier">begin</span><span class="special">,</span> <span class="identifier">BidirectionalIterator</span> <span class="identifier">end</span><span class="special">,</span> <span class="identifier">Predicate</span> <span class="identifier">p</span> <span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Range</span><span class="special">&gt;</span>
	<span class="keyword">bool</span> <span class="identifier">is_palindrome</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">Range</span> <span class="special">&amp;</span><span class="identifier">r</span> <span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Range</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Predicate</span><span class="special">&gt;</span>
	<span class="keyword">bool</span> <span class="identifier">is_palindrome</span> <span class="special">(</span> <span class="keyword">const</span> <span class="identifier">Range</span> <span class="special">&amp;</span><span class="identifier">r</span><span class="special">,</span> <span class="identifier">Predicate</span> <span class="identifier">p</span> <span class="special">);</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Predicate</span><span class="special">&gt;</span>
	<span class="keyword">bool</span> <span class="identifier">is_palindrome</span> <span class="special">(</span> <span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">str</span><span class="special">,</span> <span class="identifier">Predicate</span> <span class="identifier">p</span> <span class="special">);</span>
<span class="keyword">bool</span> <span class="identifier">is_palindrome</span><span class="special">(</span><span class="keyword">const</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">str</span><span class="special">);</span>
</pre>
<p>
      </p>
<h5>
<a name="the_boost_algorithm_library.Misc.is_palindrome.h1"></a>
        <span class="phrase"><a name="the_boost_algorithm_library.Misc.is_palindrome.examples"></a></span><a class="link" href="is_palindrome.html#the_boost_algorithm_library.Misc.is_palindrome.examples">Examples</a>
      </h5>
<p>
        Given the containers: const std::list&lt;int&gt; empty, const std::vector&lt;char&gt;
        singleElement{'z'}, int oddNonPalindrome[] = {3,2,2}, const int oddPalindrome[]
        = {1,2,3,2,1}, const int evenPalindrome[] = {1,2,2,1}, int evenNonPalindrome[]
        = {1,4,8,8}, then
</p>
<pre class="programlisting"><span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">empty</span><span class="special">))</span>  <span class="special">--&gt;</span> <span class="keyword">true</span> <span class="comment">//empty range                                                                       </span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">singleElement</span><span class="special">))</span>  <span class="special">--&gt;</span> <span class="keyword">true</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">oddNonPalindrome</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">oddNonPalindrome</span><span class="special">)))</span> <span class="special">--&gt;</span> <span class="keyword">false</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">evenPalindrome</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">evenPalindrome</span><span class="special">)))</span> <span class="special">--&gt;</span> <span class="keyword">true</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">empty</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">empty</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">functorComparator</span><span class="special">()))</span> <span class="special">--&gt;</span> <span class="keyword">true</span> <span class="comment">//empty range                             </span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">oddNonPalindrome</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">oddNonPalindrome</span><span class="special">),</span> <span class="identifier">funcComparator</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;))</span> <span class="special">--&gt;</span> <span class="keyword">false</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">oddPalindrome</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">oddPalindrome</span><span class="special">))</span> <span class="special">--&gt;</span> <span class="keyword">true</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">evenPalindrome</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">equal_to</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;()))</span> <span class="special">--&gt;</span> <span class="keyword">true</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">evenNonPalindrome</span><span class="special">),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">evenNonPalindrome</span><span class="special">))</span> <span class="special">--&gt;</span> <span class="keyword">false</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="string">"a"</span><span class="special">)</span> <span class="special">--&gt;</span> <span class="keyword">true</span>
<span class="identifier">is_palindrome</span><span class="special">(</span><span class="string">"aba"</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">equal_to</span><span class="special">&lt;</span><span class="keyword">char</span><span class="special">&gt;())</span> <span class="special">--&gt;</span> <span class="keyword">true</span>
</pre>
<p>
      </p>
<h5>
<a name="the_boost_algorithm_library.Misc.is_palindrome.h2"></a>
        <span class="phrase"><a name="the_boost_algorithm_library.Misc.is_palindrome.iterator_requirements"></a></span><a class="link" href="is_palindrome.html#the_boost_algorithm_library.Misc.is_palindrome.iterator_requirements">Iterator
        Requirements</a>
      </h5>
<p>
        <code class="computeroutput"><span class="identifier">is_palindrome</span></code> work on Bidirectional
        and RandomAccess iterators.
      </p>
<h5>
<a name="the_boost_algorithm_library.Misc.is_palindrome.h3"></a>
        <span class="phrase"><a name="the_boost_algorithm_library.Misc.is_palindrome.complexity"></a></span><a class="link" href="is_palindrome.html#the_boost_algorithm_library.Misc.is_palindrome.complexity">Complexity</a>
      </h5>
<p>
        All of the variants of <code class="computeroutput"><span class="identifier">is_palindrome</span></code>
        run in <span class="emphasis"><em>O(N)</em></span> (linear) time; that is, they compare against
        each element in the list once. If any of the comparisons not succeed, the
        algorithm will terminate immediately, without examining the remaining members
        of the sequence.
      </p>
<h5>
<a name="the_boost_algorithm_library.Misc.is_palindrome.h4"></a>
        <span class="phrase"><a name="the_boost_algorithm_library.Misc.is_palindrome.exception_safety"></a></span><a class="link" href="is_palindrome.html#the_boost_algorithm_library.Misc.is_palindrome.exception_safety">Exception
        Safety</a>
      </h5>
<p>
        All of the variants of <code class="computeroutput"><span class="identifier">is_palindrome</span></code>
        take their parameters by value, const pointer or const reference, and do
        not depend upon any global state. Therefore, all the routines in this file
        provide the strong exception guarantee.
      </p>
<h5>
<a name="the_boost_algorithm_library.Misc.is_palindrome.h5"></a>
        <span class="phrase"><a name="the_boost_algorithm_library.Misc.is_palindrome.notes"></a></span><a class="link" href="is_palindrome.html#the_boost_algorithm_library.Misc.is_palindrome.notes">Notes</a>
      </h5>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
            <code class="computeroutput"><span class="identifier">is_palindrome</span></code> returns
            true for empty ranges, const char* null pointers and for single element
            ranges.
          </li>
<li class="listitem">
            If you use version of 'is_palindrome' without custom predicate, 'is_palindrome'
            uses default 'operator==()' for elements.
          </li>
<li class="listitem">
            Be careful with using not null pointer 'const char*' without '\0' - if
            you use it with 'is_palindrome', it's a undefined behaviour.
          </li>
</ul></div>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2010-2012 Marshall Clow<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div></td>
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